One poster identified at least two vectors for the bug: Google Apps for Education, and Google Apps Password Sync.

“For those of you who have managing Chromebooks via GAFE/GAPS, Google has confirmed an issue where managed Chromebooks will 'forget' the wireless settings. In our case, we had 5 schools (so far) notify us that the cbs [Chromebooks - Ed] just lost the connection.”

Google responded, but not in a way that pleased everybody. Over at its Google for Education Help Forum, Susan Herder posted: “You may have experienced an issue today where managed Chromebooks would not automatically connect to Wi-Fi. If you manually connect to a network and login, the device will switch over to the correct network once it has received the wireless policy.”

Sysadmins with lots of student machines under their care weren't relishing the prospect of a manual reconnect of (in one case) 4,000 boxen.

Redditor “IsilZha” reckoned he was close to identifying the issue before the fix landed: “I narrowed down the issue to the 'Restrict Wi-Fi networks' option under general network settings. Removing that option restored auto connecting to your configured networks. It seems that option started restricting all Wi-Fi, including your configured ones.” ®